The Impact of High Altitude on Pre-Existing Conditions

With increasing numbers of people travelling to more remote and exotic locations, journeying to high
altitudes has becoming more popular than ever. High altitude is generally defined as any height between
1,500 and 3,500m, with 3,500 - 5,500m being classed as very high altitude and anything over 5,500m classed
as extreme altitude.[1]

Altitude sickness can occur when you move between altitudes occurs too quickly for acclimatisation to take
place effectively.[2] Mild forms of altitude sickness are known as acute mountain sickness (AMS), while
more severe forms can develop into high altitude cerebral oedema (HACO) or high-altitude pulmonary oedema
(HAPO).[3]

Symptoms of mountain sickness can change depending on what form of illness you have developed, and how
severe it is. The most common symptoms of altitude sickness include dizziness, fatigue, shortness of
breath, loss of appetite, lethargy and sleep problems. In more severe cases, these symptoms become worse
and are accompanied by headaches, nausea and vomiting, as well as a tightness in the chest. In the most
serious cases, the condition can lead to confusion, immobility and a fluid build-up in the lungs.[4]

But for those with pre-existing conditions, avoiding altitude sickness requires even more care and
planning.

High altitude and pre-existing conditions

Most people can enjoy travelling to areas of higher altitudes if the necessary care is taken, but
travellers with certain medical conditions should seek out medical advice before travelling to make sure
their condition is stable, and won’t be worsened by the altitude change.

Pregnancy also requires greater care in higher altitudes, as the World Health Organisation recommended
avoiding altitudes higher than 3000m when pregnant.[6]

Age and disability can also impact the risk of altitude sickness when travelling, so be sure to consult
your GP if you feel your chances of developing the condition may be higher.

Precautions against altitude sickness

No matter who you are and how robust your overall health is, it is vital that you take precautions when
travelling to high altitudes.

It is generally advised that you avoid travelling from altitudes less than 1,200m to altitudes greater
than 3,500m in a single day. When you reach altitudes higher than 3,000m, avoid increasing your elevation
by more than 500m a day, and make room for a rest day every three or four days.[7]

If you do begin to develop symptoms of high altitude, don’t continue to ascend. Always attempt to descend
if your symptoms worsen or become severe.[8]

Medications like acetazolamide can be used to lessen the impact of altitude sickness, aiding recovery, by
causing a mild metabolic acidosis which increases respiratory rate, improving oxygenation.[9]

You can find safe and effective altitude sickness treatment like acetazolamide right
here at Express Pharmacy. Get in touch with our pharmacists today by calling 0208 123 07 03 or by using
our discreet online Live Chat service.